Magnetic telegraphone



March 18, 1941. c. c. TOWNE I MAGNETIC TELEGRAPHONE 4 Sheets-Sheet 1 Filed July 13, 1939 FIG.

INVENTOR C. C. TOW/V5 AT TORNEV March 18, 1941. C Q TQWNE 2,235,126

MAGNETIC TELSGRAPHOHE I Filed July 13, 1939 4 Sheets-Sheet 2 FIG. 3

FIG, 4

REPRODUC RECORD (HEAR) (TALK) lNVENTOR 6.6. TOWNE ATTORNEY March 18, 1941. c g, ow 2,235,126

MAGNETI C TELEGRAPHQNE Filed July 13, 1939 4-Sheets-Sheet 3 mom BACK 1 I FORWARD smmvns Rsrumv N0. 2 mun NO. I onuu TRANDS N0. 2 man mo/vr 6 BACK 1 I ronmann STl-MjVBS I 2 -2 2 a 3 3 a I s s snu/vos no. 2 0mm N0. DRUM no. 2 0mm FIG. 7

55 57 5a 56 \4' w v F I G. 8

lNl/EN70R C. C. TOWNE' ATTORNEY March 18, 1941. c. c. TOWNE 2,235,126

MAGNETIC TELEGRAPHOI iE Filed July 135,. 1939' 4 Sheets-Sheet 4 FIG. 9

ATTOR/lEV Patented Mar. 18, 1941 monarro mmoaarnona Charles 0. Tone, summit, N. 1., assignmm Bell Telephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application July 13, 1939, Serial No. 284,155

8 Claim.

This invention relates to telegraphone systoms and the object of the invention is a telegraphone which is particularly adapted for repeated reproductions of recordings'oi different lengths.

in accordance with the general features of the invention. the recording member comprises a continuous tape wound on a plurality of rollers or drums in such a manner that no cross-over idler pulleys are required to return the tape to its starting point. In general this is accomplished by winding the portion of the tape spirally around the drums and then winding the remainder of the tape spirally back to the starting point intermediate the spiral turns oi the first portion.

The reeling apparatus is preierahly designed as a replaceable unit so that in the event oi a breakdown, or when a recording meniher oi dillierent recording time is required, a new unit may he quietly substituted with minimum disturbance to the remainder oi the system. in its slinplest form the tape storage unit comprises two spaced cylindrical drums wound in the manner described above but this winding method is also applicable to more compleir units having three or more such drums to increase the tape storage capacity. Units with three or more drums have the additional advantage that any eccentrloities in the drums are much less likely to be curnulative in their effect on the tension oi" the tape.

(these and other ieatures oi the invention will he more clearly understood irom the iollowlng detailed description and the accompanying drawings in which:

l is a perspective view ot a telegraphone according to the invention which is readily portable and particularly suitable for instruction in elocution or languages.

Fig. 2 is a perspective view and Fig. 3 is a rear view of the chassis within the casing shown in l.

Fig. t is a circuit diagram of the amplifying system oi the tclegraphone of Fig. l.

Figs. 5 and t are diagrams showing alternate methods of winding the tape on the cylindrical drums of the telegraphone. Figs. 7 and 3 show a modification oi the tape storage unit using two pairs of drums.

Figs. 9 and ill show a three-drum storage unit adapted for panel mounting;and

llig. ll shows a winding diagram for the unit oi" d and 10.

its shown in Fig. 1 the set in one form resembles'a portable radio and comprises a cabinet 5 having an-open grill 6 behind which may be located a loud-speaking telephone shown at I in the circuit diagram Fig. 4. Located at the front of the cabinet 5 near one end is an opening 8 to provide access to a talk-listen switch 9 and a clear view or the recording time indicator Ill. At its opposite end the front face of the cabinet is provided with an opening Ii adapted to expose a jack It and a, volume control potentiometer it. The jack i2 is provided to receive a plug it electrically connected with a pick-up microphone. i "to he used ior recording purposes. Bracket it carrying the talk-listen switch i1 and the recording time indicator it and a bracket it carrying the iacl: it and volume control potentiometer it are supported near opposite ends of a base ll! constituting the chassis support for the equipment oi the apparatus as shown in Figs. it and The base ii is slidable into and out of the cabinet t tor easy removal or the apparatus and in addition to the brackets it and it, it supports rotating drums iii and ill carrying a magnetic tape ill, a driving motor it supported in a well lit iorined in said base ill and the various circuit elements oi the amplifier illustrated schematically in Fig. t.

The rotating drums ill and ill with the associated tapeand cooperating parts are removable as a unit from the chassis in order to provide for ready replacement oi this part of the apparatus, and for this purpose there is provided a unitary irame structure comprising a pair or horizontal plates it and it formed integrally with a pair of ll-shaped bracket members ill and it between the legs oi which the drums it and it are rotatably supported. At their lower ends the bracket members ill and it are attached to horizontal members it and lit adapted to rest upon and be bolted to supporting studs it, it, it and it secured to and extending upwardly from the base ill. The upper horizontal plate 2% is provided with a mounting plate 35 for supporting a recording-reproducing head it, and a spring tenstoned supporting arm ill mounted upon the plate it supports a tape tensioning pulley The connections from the recording-reproducing head to the circuit of the amplifier loud-speaker and microphone pick-up are by means of a cable ti that extends through a hole ll in the horizontal plate it and terminates in a plug it that makes connections with a socket in the base ill. The motor it is connected by a belt it with a set of pulleys mounted upon the lower face of the horizontal plate 25 and a second belt from this pulley combination runs around the drum it by means of which the tape is drawn through the recorder-reproducer head. To remove the tape unit requires only the unbolting of the drum supporting structure from the posts 3|, 32, 33 and 34, disconnection of the belt 43 from the motor ZI and pulling out of the plug 42 from -its socket and a corresponding new reeling unit can be inserted. I

The tape 20 as illustrated in Figs. 2 and 3 is in the form of a continuous loop, and the recorderreproducer head 36 is stationary and in order to bring the tape back to its starting position with respect to the sound-head without using special cross-over pulleys or putting undue trans- 'V8IS8 pressure upon the tape either of the two interleaving schemes shown in Figs. 5 and 6 may be used. In the scheme shown in Fig. 5 the crossover of adjacent loops of the tape occurs both at the front and back of the drums while in Fig. 6 the cross-over occurs only at the back.

For example, starting with the top loop of the tape which is the one that will be passing through the sound-head, it will be noted that from position I of the No. 1 drum the tape will reach to position 2 on the No, 2 drum and from position 2 on the No. 2 drum it will pass over position 3 on the No. 1 drum to position 4 on the No. 2 drum and from position 4 on the No. 2 drum through position 5 on the No. 1 drum to position 5 on the No. 2 drum. From position 5 on the No. 2 drum the tape will pass back through position 4 on the No. 1 drum to position 3 on the No. 2 drum, back through position 2 on the No. 1 drum to position I on the No. 2 drum, and back to the starting point on the No. l drum.

In the scheme shown in Fig. 3 in which the cross-over occurs only at the back side of the drums the tape passes from the I position on the No. 1 drum to the 3 position on the No. 2 drum through the 3 position on the No. 1 drum to the 5 position on the No. 2 drum, back through 5 of No. 1 to 4 of No. 2, over 4 on No. 1 to 2 on No. 2, over 2 on No. 1 to I on No. 2 and back to the starting point on No. 1.

The relative position of adjacent spirals of tape are maintained on the drums I8 and I9 by means of multiple sheaves and 46 mounted on the horizontal plate 25 and extending in parallel relation to their respective drums adjacent the advance surface thereof. Separators 41 and 48 secured to the frame supporting the drums I8 and I9, midway between the drums maintain the adjacent spirals of the tape 20 separated adjacent their cross-over positions. Vertical rods -49 and 50 extending upwardly from the plate 25 adjacent the multiple sheaves and parallel thereto maintain the parallelism of the spirals adjacent the sheaves 45 and 46.

The tape storage capacity may be very materially increased Without increasing the total overall space occupied by the drums by means of the arrangement shown in Figs. 7 and 8. In this modification, there are two main drums and 56 and two intermediate drums 51 and 58 positioned between the drums 55 and 56 and the tape loop is coiled around the main drums 55 and 56 in a spiral running from the top of these drums to the bottom and the bottom spiral from these drums 55 and 56 is fed onto the lower ends of the drums 51 and 58 and coiled around them in a spiral running from bottom to top, the top loop from these drums being fed back onto the drums 55 and 56 at the tops of these drums. The length of tape effective for recording is by this means increased by the length that can be stored upon the drums 51 and 58.

The foregoing description of apparatus applies especially to a horizontal portable type of machine particularly adapted for use in educational work.

Where it is desired to extend the usefulness to other fields where greater storage space for tape and permanency is desirable and where space may be somewhat limited a vertically mounted type such as illustrated in Figs. 9 and 10 may prove very convenient.

In this type a mounting panel 60 for the apparatus is removably mounted upon a supporting frame of channel pieces 6| and 62 which may be conveniently supported. Rotatably supported upon the face of the panel 60 at the points of a triangle are three tape drums 63, 64 and 65 carrying a tape 66 which is adapted to be guided through a recording-reproducing head 61 mounted upon the panel 60 midway between the tape rolls 64 and 65. The drive for the rolls is through roll 63 connected to a pulley 68 mounted on the back of the panel 60 and connected by belt 69 with a synchronous motor Ill. The motor I0 is mounted upon a bracket 'II pivotally supported upon a stub shaft I2 secured to the back of the mounting plate 60 so that the weight of the motor maintains the driving tension on belt 69. Located between the drums 63 and 64 is a spring mounted tensioning pulley I3 under which the first spiral of the tape 66 passes before passing 0 over drum 64 into the recorder-reproducer head 61.

The same general scheme for interleaving the tape spirals is followed in this three-drum modiflcation as was followed in that disclosed in Figs.

,case letters a to t in alphabetical order on the developed views in Fig. 11.

Guide sheaves I5, I6 and TI secured to the plate 60 in advance of the drums 63, 64 and 65, respectively, serve to maintain the adjacent spirals of tape in properly spaced positions upon the drums. Spreader rods I6 and I9 located between drums 63 and 64 and drums 65 and 63,

respectively, serve to separate the tape spirals adjacent their cross-over positions to prevent clashing or rubbing of adjacent layers of the tape.

The mounting plate with its associated apparatus may be used as a unit for ready replacement should the tape of the one in use break or the apparatus be otherwise disabled.

By using the three drums a greater storage space is provided and the combination has the additional advantage that eccentricities in the drums are less likely to be accumulative in their eiiect upon the tension of the tape.

A circuit combination suitable for use with the apparatus illustrated in Figs. 1, 2 and 3 is illustrated schematically in Fig. 4. This circuit comprises in general a conventional amplifier of voice currents supplied with filament and plate current through transformer and rectifier from a commercial sixty-cycle source. The double throw switch 9 already mentioned in the description of the cabinet of Fig. 1 is wired in circuit with the sound-head 36, loud-speaker 'I and microphone 4 and is adapted when moved to the right of its normal position to connect the microphone with the input side of the amplifier and to connect the output side of the amplifier with the voice coil 80,

of the recorder-reproducer I. When moved to the left, as shown, switch I connects the coil "of the recorder-reproducer with the input side or the amplifier and the output side of the amplifier to the energizing winding oi the loud-speaker I.

A socket I! in base I1 is adapted to receive a plug wired to the ordinary house or commercial source of current.

The amplifier and switching equipment for the recorder-reproducer apparatus illustrated in Figs. 9, l and 11 may be mounted upon a panel (not shown) which will be mounted upon the same frame as the mounting plate I or one similar to it.

The tape in strip form may be threaded onto the reels in the spiraled relation in which it is to be operated and the loose ends secured to form the loop by welding.

What is claimed is:

i. it tape storage and carrying unit for telegraphones comprising a plurality of rotatable drums mounted in. spacedrelation, and a continuous magnetictapefspiraled around the drums with adjacent 'spirals'fso' relatedthatany given point on the tape will move axiallyot the drums from end to end and back to its starting position in one complete cycle of travel of the tape loop.

2. A' tape storage and carrying unit for telegraphones comprising a plurality of rotatable drums mounted in spaced relation and a loop of magnetic tape continuously spiraled around the drums with substantially one-half of its length forming a first spiral in one direction axially of the drums and the remainder of the tape forming a return spiral intermediate the turns of the first spiral.

3. In a telegraphone apparatus in combination, a plurality of tape carrying drums rotatably mounted in spaced relation, and a continuous magnetic tape spiraled around the drums with adjacent spirals so interleaved that any given point on the tape will move axially oi the drums from end to end and back to its starting point in one complete cycle of travel or the tape loop;

4. In a telegraphone apparatus in combination, a plurality of tape carrying drums rotatably mounted in spaced relation, 9. continuous magnetic tape spiraied around the drums with adiacent spirals so interleaved that a given point on the tape will move axially oi the drums from end to end and back to its starting position in one complete cycle of travel of the tape loop, and guide sheaves located adiaeent the advance edBes of the drums for maintaining the relative positions of adjacent loops of the spiral over the faces of the drums.

5. In a telegraphone apparatus in combination, a plurality of tape carrying drums rotatably mounted in spaced relation, a continuous magnetic tape spiraled around the drums in interleaved relation with alternate loops crossed over each other between the drums and separators located midway between the drums for maintaining a spaced relation between the adjacent coils at the cross-over position.

6. In a telegraphone. apparatus in combination, a plurality or tape carrying drums rotatably mounted in spaced relation, a continuous magnetic tape spiraled around the drums in interleaved relation with alternate loops oi the spiral crossed over between the drums, separators located between the drums ior maintaining a spaced relation between the adjacent layers at the cross-over position and guide sheaves located in advance of each drum for leading the coils of the spiral onto the faces of the drums in fixed spaced relation.

7. In a portable telegraphone in combination, a continuous magnetic'tape, .a recorder-reproducer head cooperating with the tape, a plurality of rotatable drums for carrying the tape in cooperative relation to the recorder-reproducer head, a driving motor for the drums, an amplifier, switching means for connecting the recorder reproducer alternately in input and output relation to the amplifier, a casing, a removable chassis in the casing supporting the motor, ampliher and telegraphone equipment, and supporting 3 means for the drums and recorder-reproducer head removably mounted upon the chassis.

8. In a portable telegraphone in combination, a continuous magnetic tape, a recorder-reproducer apparatus cooperating with the tape, a pair of rotatable drum for moving the tape in cooperative relation to the recorder-reproducer head, a 1

support for the drums and recorder-reproducer head, a chassis upon which the support for the drums is removably supported, a driving motor for the drums supported upon the chassis, amplifier equipment mounted'on the chassis, switching means carried by said chassis for selectively connecting the recorder-reproducer apparatus in input or output relation to the recorder-reproducer apparatus, and a casing in which the chassis is removably supported.

- CHARLESCJIOWNE. 

